1. Field of the Invention
The present invention relates to a waterproof slide fastener in which a fastener tape thereof is coated with a waterproof layer composed of elastomer resin or the like, and more particularly, to a waterproof slide fastener in which a fastener tape having a waterproof layer on a surface of a woven or knitted belt-like core material is equipped with a separable bottom end stop, the waterproof slide fastener being capable of preventing an insert pin of the separable bottom end stop from dropping out of the fastener tape.
2. Description of the Related Art
A waterproof slide fastener is manufactured as follows. First, a fastener tape having a waterproof layer is produced by covering an entire surface of a belt body woven or knitted with fibers as a core material with natural rubber, synthetic rubber or elastomer resin composed of various synthetic resins. Then, fastener elements made of synthetic resin are molded integrally by injection molding such that each of them strides across front and rear faces along a side edge of the fastener tape. A pair of fastener stringers is obtained in the aforementioned way. Each of the fastener stringers having such a waterproof layer formed therein can block water from penetrating into the belt-like core material even if water adheres to a surface thereof.
After a slider is inserted through a fastener element row of one of the pair of fastener stringers thus obtained, a box pin is formed at a bottom end of the fastener element row of the fastener stringer so as to be continuous from the fastener element row and a box is molded integrally with the box pin as a separable bottom end stop. Further, an insert pin is mounted at a bottom end of a fastener element row of the other fastener stringer so as to be continuous from the fastener element row. Then, the fastener stringer having the box pin and the box mounted thereon and the fastener stringer having the insert pin mounted thereon are combined to produce a waterproof slide fastener.
As regards such a waterproof slide fastener, for example, Japanese Patent Application Laid-Open Publication No. (JP-A) 2005-237577 has disclosed a waterproof slide fastener in which a fixing strength between a fastener tape and fastener elements and a waterproof property of the slide fastener are improved, the slide fastener enabling a sliding operation of a slider to be executed more lightly.
The waterproof slide fastener 50 disclosed in JP-A 2005-237577 and shown in FIG. 21 is a slide fastener 50 having a waterproof structure comprised of a pair of fastener stringers 52 and a slider (not shown). In the pair of fastener stringers 52, a plurality of fastener elements 61 are molded integrally along opposing element mounting edges 51 of a pair of waterproof fastener tapes 55 each having a waterproof layer on its belt-like core materials. The slider engages/disengages the fastener elements 61. The slide fastener 50 has following characteristics.
That is, each fastener element 61 molded integrally on the fastener tape 55 comprises a coupling head 62, a neck portion 63, a body portion 64, a shoulder portion 65, and leg portions 66 extending from the body portion 64 inward of the fastener tape 55. The coupling head 62, the neck portion 63, the body portion 64, the shoulder portion 65 and the leg portions 66 are included in each of upper and lower half portions formed on front and rear faces of the fastener tape 55. The half portions are integrated by a connecting portion 67 through a through hole 54 formed in an element mounting edge portion 51 of the fastener tape 55. As a consequence, each fastener element 61 can be fixed firmly to a predetermined position of the fastener tape 55.
An edge 53 of the element mounting edge portion 51 is extended beyond the neck portion 63 of the fastener element 61, and a gap is formed between the upper and lower half portions of the coupling heads 62, so that when the fastener elements 61 are engaged, end faces of a pair of opposing fastener tapes 55 make a firm contact with each other. As a consequence, water or the like is blocked from penetrating from the front face to the rear face of the fastener tape 55 when the fastener elements 61 are engaged.
In the waterproof slide fastener described in JP-A 2005-237577, each half portion of the shoulder portion 65 and the leg portion 66 of the fastener element 61 is formed with a smaller thickness in a direction intersecting the front and rear faces of the fastener tape at right angle than each half portion of the neck portion 63 and the body portion 64. Two or more upper and lower half portions of the leg portion 66 are formed at a required interval in a sliding direction of the slider.
Consequently, when the slider is slid along the fastener elements 61, upper and lower flange portions of the slider are guided by the upper and lower half portions of the leg portions 66 of the fastener elements 61 in a sliding manner. For this reason, a sliding area in which the flange portions of the slider make a sliding contact with the leg portions 66 of the fastener elements 61 decreases. As a result, sliding resistance when the slider is slid can be decreased to allow the sliding operation of the slider to be executed smoothly. Further, according to JP-A 2005-237577, it has been said that the fixing strength of the fastener elements 61 to the fastener tape 55 can be increased by providing the fastener elements 61 with the leg portions 66.
In a normal type slide fastener with a separable bottom end stop in which no waterproof layer is formed in its fastener tapes like ones used ordinarily in an opening/closing portion of clothes or the like, the separable bottom end stop is hard to operate, that is, an operation of inserting the insert pin into the box is not easy to perform because elasticity of the fastener tape is high. Thus, in order to smoothly operate the separable bottom end stop, it has been known to stabilize a tape configuration by reinforcing a front end portion of each of the fastener tapes, for example, in such a manner that a reinforcing member such as a reinforcing rib is attached near the separable bottom end stop of the fastener tape.
For example, Japanese Patent Application Laid-Open Publication No. (JP-A) 2004-283299 has disclosed a slide fastener with a following configuration. That is, a pair of fastener tapes each having an element mounting edge portion including a woven or knitted core thread are woven or knitted, and a plurality of fastener elements are arranged along element mounting edge portions opposing each other of the pair of woven or knitted fastener tapes. A slider is inserted through the fastener elements, and a separable bottom end stop comprised of an insert pin, a box pin and a box is mounted to one end portion of the pair of fastener tapes. The slide fastener with the separable bottom end stop has following characteristics.
In the slide fastener with the separable bottom end stop described in JP-A 2004-283299, a reinforcing portion molded integrally with the separable bottom end stop is provided on at least one face of the fastener tape, the reinforcing portion is comprised of an inner side portion adjoining the separable bottom end stop and an outer side portion extending from the inner side portion, and the inner side portion and the outer side portion are constituted of a plurality of ribs.
In such a slide fastener with the separable bottom end stop, one end portion of the elastic fastener tape is reinforced by the reinforcing portion, so that its configuration is stabilized. Accordingly, for example, when the insert pin of the separable bottom end stop is inserted into the box provided on the other fastener stringer, an operation of inserting the insert pin into the box can be carried out stably by holding the reinforced end portion of the fastener tape. Further, the slide fastener of JP-A 2004-283299 can disperse an external force effectively by the ribs on the inner side even if a bending force or twisting force is applied to the end portion of the fastener stringer. In addition, the reinforcing portion can be deformed easily, thereby preventing the reinforcing portion from being damaged.
On the other hand, in the above-described waterproof slide fastener, for example, a configuration of the fastener tape itself is relatively stabilized because the fastener tape is covered with elastomer resin. For this reason, even if the reinforcing portion constituted of a plurality of ribs as disclosed in JP-A 2004-283299 or another reinforcing member is not provided in a vicinity of the separable bottom end stop of the waterproof slide fastener, the operation of inserting the insert pin into the box can be executed stably. If stiffness of the fastener tape is intensified by providing a reinforcing member and the like, the elasticity of the fastener tape is lost, so that the fastener tape cannot be deformed appropriately when the insert pin is inserted into the box, thereby possibly blocking an operation of smoothly inserting the insert pin. For this reason, generally, an end portion of the conventional waterproof slide fastener is provided with no reinforcing member, etc., but only with the separable bottom end stop.
In the waterproof slide fastener, the fastener tape is covered with elastomer resin in advance as described above, in order to secure a waterproof characteristic. Thus, when the fastener elements or the separable bottom end stop such as the insert pin is formed on an element mounting edge portion of the fastener tape by injection molding, resin material of the fastener element hardly penetrates into an inside of the tape as compared with an ordinary slide fastener having a fastener tape not coated with resin. As a consequence, the fixing strength of the fastener elements or the separable bottom end stop to the fastener tape decreases, which has been a problem to be solved.
The waterproof slide fastener 50 described in JP-A 2005-237577 is constituted such that the end faces of opposing fastener tapes 55 on element mounting edge portion sides make a firm contact with each other when the fastener elements 61 are engaged in order to enhance the waterproof property. Consequently, penetration of water or the like into a rear side from a front side of the slide fastener 50 is prevented. On the other hand, such a waterproof slide fastener 50 includes no core thread in the element mounting edge portions 51 for the reason of a constitution which brings the end faces of the fastener tapes 55 into a firm contact with each other sufficiently. For this reason, the waterproof slide fastener 50 of JP-A 2005-237577 needs to include a through hole 54 formed in the element mounting edge portion 51 in order to fix the fastener element 61 to the element mounting edge portion 51 firmly so that the upper and lower half portions of the fastener element 61 are fixed integrally by a connecting portion 67 through the through hole 54.
However, in an insert pin mounted on one end portion of the fastener tape 55, an insert pin mounting width from an edge of the fastener tape 55 is small because its configuration is narrow. Additionally, in a front end area of the fastener tape 55 on an insert pin fixing side, a front end portion (particularly a corner portion) of the fastener tape 55 is partially cut out when the insert pin is injection molded so as not to be exposed on an outer face of the insert pin. As a result, a contact area (fixing area) between the insert pin and the fastener tape 55 is very small.
The insert pin itself (particularly, a portion (groove) which nips the fastener tape 55) is easy to deform because its thickness is relatively small, and the insert pin likely receives a tensile stress or torsion as compared with the fastener element 61 when the slide fastener 50 is used.
Therefore, the waterproof slide fastener 50 having no core thread on its element mounting edge portion 51 has a following problem. That is, the insert pin is likely to slip out of the fastener tape 55 because the fixing strength of the insert pin is low and a portion nipping the fastener tape 55 of the insert pin is deformed and widened when it receives a stress or torsion during usage. Further, it can be considered to form the insert pin itself in a large size and in a large thickness to prevent the insert pin from slipping out. In this case, however, an elasticity of the fastener tape 55 is lost, thereby disabling operation of inserting the insert pin into the box.
When the operation of inserting the insert pin is repeated in the conventional waterproof slide fastener 50, the front end face of the fastener tape on the insert pin fixing side makes contact with a shoulder mouth of the slider, and a front end area of the fastener tape rubs against flanges of the slider. For this reason, the waterproof layer applied to the fastener tape 55 is worn, so that the fastener tape is likely to be unraveled or damaged. Consequently, waterproof performance of the slide fastener 50 is dropped.